Water-based drilling fluid additive containing talc and graphite

ABSTRACT

A drilling fluid additive is provided wherein the additive is manufactured by a method comprised of admixing at least one carrier such as a polypropylene glycol to talc and subsequently admixing graphite to the talc and carrier mixture; and then admixing an uintaite to the talc, carrier and graphite mixture.

RELATED APPLICATION

[0001] This application is a continuation-in-part of U.S. applicationSer. No. 10/090201, entitled “Water-Based Drilling Fluid AdditiveContaining Talc & Carrier” which was filed on Mar. 5, 2002.

BACKGROUND OF THE INVENTION

[0002] 1. Field of the Invention

[0003] The present invention relates to a drilling fluid additivecomprising: talc, graphite and at least one carrier. More specifically,the present invention relates to a drilling fluid additive manufacturedby a method comprising: admixing talc, graphite and at least onecarrier, wherein the carrier is selected from a group consisting ofoils, esters, glycols, cellulose, olefins and mixtures thereof.

[0004] 2. Description of the Related Art

[0005] New technology in drilling for oil and gas now includeshorizontal drilling. The horizontal drilling concept exposes moresurface area of the producing zone than the conventional verticaldrilling operations. For example, if a producing zone is fifty feet inthickness and a vertical well is drilled through such a zone, then onlyfifty feet of the producing zone will be exposed for production. Incontrast, a horizontally drilled well may penetrate the producing sandor zone by one thousand feet or more. The amount or volume of oil or gasproduction is directly proportional to the horizontal penetration infeet into the producing sand or zone. In horizontal or directionaldrilling where the drill pipe must bend in order to achieve the desiredpenetration into the producing zone, friction becomes a major problem.The primary source of friction is directly related to the adhesion ofthe drilling assembly to the wall cake which lines the drilled wellbore. The capillary attractive forces generated by the adhesion of thedrilling assembly to the wall cake are directly proportional to theamount or footage of the drilling assembly exposed to the surface of thewall cake.

[0006] In horizontal or directional wells, many methods have been usedin order to reduce friction between the drilling assembly and the wallcake. One such method would be to add a liquid lubricant to the drillingfluid in order to reduce the coefficient of friction of the drillingfluid. These liquid lubricants include oils, such as hydrocarbon basedoils, vegetable oils, glycols, etc. These liquid lubricants will usuallyreduce the coefficient of friction of the drilling fluid resulting in areduction of friction between the drilling assembly and the wall cake ofthe well bore.

[0007] When the liquid lubricant is added to the drilling fluid, it hasseveral options as to how it will react. One option is that thelubricant remains isolated and does not mix well with the drillingfluid. A second option is that the lubricant emulsifies with the waterin the drilling fluid to form an oil-in-water emulsion. Still anotheroption is the oil attaching itself to the commercial solids in thedrilling fluid or to the drilled cuttings or drilled solids. In certaincircumstances, some of the liquid lubricant might be deposited orsmeared onto the wall cake of the well bore. The ideal scenario would beto have all of the liquid lubricant deposited on the wall cake.

[0008] Those experienced in drilling fluid engineering know that a thin,tough, pliable, and lubricious wall cake is most desirable. Theintegrity of a wall cake is determined by several factors. The thicknessof a wall cake is directly proportional to the amount of liquid leavingthe drilling fluid, and being forced into the wall of the well bore byhydrostatic pressure. The thickness of the wall cake is also determinedby the type and particle size of the solids in the drilling fluid.Particle Size Distribution, or PSD is important to the wall cakeintegrity. Experts in drilling fluids also know that materials such asbentonite clay, starches, lignites and polymers are all used to buildacceptable wall cakes. It is known in the prior art that various foodgrade vegetable oils are acceptable lubricants when used alone inwater-based drilling fluids. It is also known in the prior art thatround co-polymer beads when used alone in water-based drilling fluidsfunction as a good friction reducer. However, much more is required toimprove the wall cake integrity and lubricity of most well bores. Inaddition, there is no technology or process in the prior art thatimproves the lubrication or friction reducing capacity of the copolymerbeads.

[0009] Furthermore, the solids control equipment used on the drillingrigs today is far superior as to what was used 15 to 20 years ago. Inthe past, drilling rig shale shakers would probably be limited to screensizes of about 20-40 mesh on the shakers. These coarser mesh screenswould allow pieces of shale and the drilled formation to pass throughthe shaker screens back into the drilling fluid and then recirculatedback down the well bore. As these larger than colloidal size particlesmake their way back up the well bore to the surface, the action of thedrilling assembly rotating within the well bore forces these largerparticles into the surface of the well bore. For example: a 20×20 meshshaker screen would allow a drilled cutting sized at 863 microns or0.0340 inches to pass through it and then the cutting would be returnedto the well bore and some of these 863 micron cuttings would eventuallybe embedded into the wall cake. This would give the wall cake surface atexture resembling that of coarse sandpaper. These larger particleswould allow the drilling fluid to channel and pass between the drillingassembly and the wall cake thereby reducing the negative effect of thecapillary attractive forces generated by the close contact of thedrilling assembly with the wall cake. The instances of the drillingassembly becoming stuck to the wall cake when less efficient solidscontrol equipment, such as shale shakers, was used much less than it istoday. The more efficient shale shakers today are a great improvementfor the drilling fluids but the instances of sticking the drillingassembly are higher. The reason for a higher rate of stuck drillingassemblies today could be blamed on cleaning the drilling fluid toefficiently. Today many drilling rigs utilize cascading shale shakers,which eventually pass the drilling fluid through 200 mesh or 74 micronscreens. This is very positive for controlling the percentage of drilledsolids in the drilling fluid but it also affects the texture or surfaceof the wall cake. The finer the solids on the surface of the wall cakeare, the greater the capillary attractive forces will be between thedrilling assembly and the wall cake.

[0010] The present invention provides a method of enhancing the surfaceof the wall cake. In order to accomplish this, the invention provides amethod, which adds something to improve the texture of the surface ofthe wall cake, and then adds something to prevent large amounts of waterfrom leaving the drilling fluid then passing through the wall cake intothe formation. The present invention also provides a carrier for thecolloidal solids and beads, which also acts as a lubricant for thedrilling fluid. The present invention further provides a process thatreduces the effect of capillary attractive forces between the drillingassembly and the wall cake, thereby reducing the tendency of thedrilling assembly to become stuck. In high angle directional wells wheredown hole motors are used to rotate the drill bit and the drill piperemains stationary, it is important that the drilling assembly can“slide” as the drilling bit cuts more holes. The present inventionimproves the ability to “slide” while drilling as stated above.

[0011] The drilling fluid additive of the present invention has thefollowing functions: borehole stability; shields water sensitive shales;is a superior pore throat sealer; seals depleted sands andmicrofractures; and lowers HTHP/dynamic filtrate. In addition, theadditive of the present invention also provides the following benefits:low spurt loss in sands; reduces hole reaming and fill; and near gaugehole. The drilling fluid additive of the present invention alsofunctions as a partial plugging agent. For purposes of this invention,the term “partial plugging agent (PPG)” is defined as a product thatwholly or partially plugs up a hole.

SUMMARY OF THE INVENTION

[0012] In one embodiment, the present invention relates to a drillingfluid additive comprising: admixing talc, graphite and at least onecarrier. In another embodiment, the drilling fluid additive of thepresent invention further comprises uintaite (sold under the trademark“Gilsonite”). In still another embodiment, the carrier comprisespolypropylene glycol. In yet another embodiment, the carrier is selectedfrom a group consisting of oils, esters, glycols, cellulose, olefins andmixtures thereof

[0013] In still yet another embodiment, the talc comprises from about 1%to about 20% of the additive, the graphite comprises from about 1% toabout 30% of the additive, the carrier comprises from about 50% to about90% of the additive and the uintaite comprises from about 1% to about40% of the additive.

[0014] In a further embodiment, the carrier is selected from a groupconsisting of polypropylene glycol polyethoxylated glycol polybutyleneglycol polyethylene glycol propylene glycol polyesterpolyol-poly(oxyethylene-oxy) propylene glycol, polyoxyalkylene glycolethers and mixtures thereof In still a further embodiment, the uintiateis treated with a second carrier. In yet a further embodiment, thesecond carrier is selected from a group consisting of oils, esters,glycols, cellulose, olefins and mixtures thereof In still yet a furtherembodiment, the second carrier comprises an ethoxylated glycol.

[0015] In another embodiment, the present invention relates to adrilling fluid additive manufactured by a method comprising: admixingtalc, graphite and at least one carrier. In still another embodiment,the carrier is first admixed with the talc and then the graphite isadmixed. In yet another embodiment, the further comprising admixing anuintaite with the carrier, talc and graphite mixture.

[0016] In still yet another embodiment, the carrier is selected from agroup consisting of oils, esters, glycols, cellulose, olefins andmixtures thereof In a further embodiment, the uintaite is pre-treatedwith a second carrier prior to being admixed to the carrier, talc andgraphite mixture. In another embodiment, the second carrier consistsessentially of oils, esters, glycols, cellulose, olefins and mixturesthereof

[0017] In yet another further embodiment, the present invention alsorelates to a method of manufacturing a drilling fluid additive, themethod comprising: admixing talc with at least one carrier; and admixinggraphite to the talc and carrier mixture. In still yet another furtherembodiment, the method further comprising admixing an uintaite with thetalc, carrier and graphite mixture.

[0018] In another embodiment, the uintaite is pretreated with a secondcarrier prior to admixing said uintaite to the talc, carrier andgraphite mixture. In a further embodiment, the first and second carriersare selected from a group consisting of oils, esters, glycols,cellulose, olefins and mixtures thereof.

[0019] Graphite

[0020] Graphite has been used for many years as a lubricant. Thelubricating mechanism of graphite is thought to be mechanical in natureand results from the sliding of one graphite particle over anothergraphite particle. Graphite may be used as a dry lubricant or may bedispersed in lubricating oil. Graphite particles may also beincorporated into a grease product for improved lubrication. Becausegraphite has the reputation for being a superior lubricant, variousgrades of graphite were tested in various water-based drilling fluid. Itwas concluded that dry graphite added to a water-based drilling fluidreduced the friction very little. One of the objectives of the presentinvention is to improve the lubricating qualities of graphite in awater-based drilling mud. Since all the tests using dry graphite provedunsuccessful, it was determined that the surface of the graphite washydrophobic or organophilic. The process of the present invention allowsthe graphite to be surface coated with the glycol carrier rendering thesurface of the graphite particles hydrophilic.

[0021] Another problem with adding untreated graphite to a water-baseddrilling fluid, which contains a percentage of oil (either animal,vegetable or hydrocarbon oil), is that the graphite has a propensity tomigrate to the oil and form an oil-wet slurry. The slurry is screenedout over the fine mesh rig shaker and the slurry containing the graphiteis lost. Another object of the present invention is to prevent thegraphite from migrating to the oil and being discarded during thescreening process. The carrier coating process of the present inventionallows the coated graphite particles to remain dispersed throughout themud system

[0022] Another object of the present invention was to successfullysuspend the graphite in a dispersion with a glycol carrier so that thecarrier would not settle to the bottom of the container and be unusable.The carrier-coated graphite of the present invention acts as anexcellent fluid loss additive thereby improving the filter cakeintegrity of the water-based mud. The hydrophilic, glycol-coatedgraphite particles would seem to be ideal particle pluggers and it isbelieved that the graphite particles or platelets would stack one on topof the other. In a further embodiment and in order to create asuspension of graphite in a glycol carrier with an extended shelf life,it was determined that additional solids having a specific gravity ofapproximately 1 to 1.2 might improve the suspension. In anotherembodiment, the present invention adds uintaite to improve thesuspension

BRIEF DESCRIPTION OF THE DRAWINGS

[0023] The accompanying drawings are included to provide a furtherunderstanding of the present invention. These drawings are incorporatedin and constitute a part of this specification, illustrate one or moreembodiments of the present invention, and together with the description,serve to explain the principles of the present invention.

[0024]FIG. 1 is a graph representing talc particle size versus volume inpercent; and

[0025]FIG. 2 is a graph representing the percent of beads suspended inoil versus the talc concentration as percent by weight of oil.

[0026] Among those benefits and improvements that have been disclosed,other objects and advantages of this invention will become apparent fromthe following description taken in conjunction with the accompanyingdrawings. The drawings constitute a part of this specification andinclude exemplary embodiments of the present invention and illustratevarious objects and features thereof.

DETAILED DESCRIPTION OF THE INVENTION

[0027] As required, detailed embodiments of the present invention aredisclosed herein; however, it is to be understood that the disclosedembodiments are merely exemplary of the invention that may be embodiedin various forms. The figures are not necessary to scale, some featuresmay be exaggerated to show details of particular components. Therefore,specific structural and functional details disclosed herein are not tobe interpreted as limiting, but merely as a basis for the claims and asa representative basis for teaching one skilled in the art to variouslyemploy the present invention.

[0028] The present invention relates to a uintaite-based(Gilsonite™-based) dispersion fluid that is environmentally safe; passesLC50; and has no sheen. For purposes of this invention, “LC50” isdefined as an acceptable environmental guideline. The term “sheen” isdefined as an oil film or coating. The drilling fluid additive of thepresent invention has a 1.08 specific gravity and is temperature stable.

[0029] The present invention provides a process that includes selectingspecific materials having different particle sizes and then pre-wettingeach particle with an environmentally acceptable lubricant prior toadding these particles to the water-based drilling fluid. This processproduces much improved wall cake integrity and lubricity. The presentinvention also teaches that food grade vegetable oils are excellentcarriers for various solid friction reducers and wall cake enhancers.The present invention has also discovered that pre-wetting the roundcopolymer beads with a food grade vegetable oil prior to adding thecopolymer beads to the drilling fluid improves the lubrication orfriction reducing capacity of the copolymer beads. The other criterionis that the products and its components have to be environmentallyfriendly.

[0030] Talc & Carrier:

[0031] In accordance with the manufacturing process of the presentinvention, talc powder is sheared with an environmentally friendly oilor liquid lubricant, which repels water. The shearing should continueuntil each or most of the organophilic or hydrophobic talc particles arecoated with the oil or liquid lubricant. In one embodiment, the talcpowder most preferred would be one with a particle size from about 1micron to about 20 microns and one which would produce a bell shapedcurve having the majority of the particles in the 2 micron to 8 micronsize, as shown in FIG. 1.

[0032] The polymeric beads of the present invention should be a solidparticle, preferably round and have a specific gravity close to 1.0 andhave a size from about 100 microns to about 900 microns. The beads mustalso have an affinity for oils, esters, olefins and glycols, etc. It wasdetermined that a copolymer bead manufactured by Dow Chemical comprisedof styrene and divinylbenzene would be acceptable.

[0033] The colloidal solids of the present invention should have a sizerange of 2-10 microns since tests have proven that this particle sizewill bridge sandstone having a permeability of 200 md. The solids mustalso have an affinity for oils, esters, olefins and glycols, etc. In oneembodiment, the solids are talc. The talc of the present invention alsofunctions as an excellent suspending agent in both oils and glycols.FIG. 1 depicts a graphical representation of the particle size of talcand Table 1, as set forth below, represents the result statistics forthe particle size for talc: TABLE 1 Particle Size Statistics For TalcDist. Type: Vol Concentration = 0.0136% Vol Density = 2.650 g/cub. cmSpec. SA = 0.5176 sq. m/g Mean Diameters: D (v, 0.1) = 2.40 um D (v,0.5) = 5.28 um D (v, 0.9) = 11.68 um D [4, 3] = 6.30 um D [3, 2] = 4.37um Span = 1.760E+00 Uniformity = 5.495E−01 Size Low (um) In % Size High(um) Under % 0.31 0.00 0.36 0.00 0.36 0.00 0.42 0.00 0.42 0.00 0.49 0.000.49 0.00 0.58 0.00 0.58 0.00 0.67 0.00 0.67 0.00 0.78 0.00 0.78 0.000.91 0.00 0.91 0.02 1.06 0.02 1.06 0.32 1.24 0.35 1.24 0.94 1.44 1.291.44 1.83 1.68 3.12 1.68 2.51 1.95 5.62 1.95 2.94 2.28 8.57 2.28 5.052.65 13.62 2.65 6.89 3.09 20.51 3.09 7.96 3.60 28.47 3.60 7.81 4.1936.29 4.19 8.89 4.88 45.18 4.88 9.49 5.69 54.67 5.69 9.05 6.63 63.726.63 8.60 7.72 72.33 7.72 7.61 9.00 79.94 9.00 6.35 10.48 86.29 10.485.02 12.21 91.31 12.21 3.70 14.22 95.01 14.22 2.47 16.57 98.95 16.571.46 19.31 99.68 19.31 0.73 22.49 100.00 22.49 0.27 26.20 100.00 26.200.05 30.53 100.00 30.53 0.00 35.56 100.00 35.56 0.00 41.43 100.00 41.430.00 48.27 100.00 48.27 0.00 56.23 100.00 56.23 0.00 65.51 100.00 65.510.00 76.32 100.00 76.32 0.00 88.91 100.00 88.91 0.00 103.58 100.00103.58 0.00 120.67 100.00 120.67 0.00 140.58 100.00 140.58 0.00 163.77100.00 163.77 0.00 190.80 100.00 190.80 0.00 222.28 100.00 222.28 0.00258.95 100.00 258.95 0.00 301.68 100.00

[0034] The carrier of the present invention may be selected fromdifferent oils, olefins, esters, fatty acids, cellulose and glycols. Inanother embodiment, the carrier may be synthetic oils, diesel oils, riceoils, cottonseed oils, corn oils, safalour oils, lnseed oils, coconutoils, vegetable oils, mineral oils, animal oils and paraffin oils. Instiff another embodiment, the carrier is soybean oil. The oil coating onthe hydrophobic talc particles enhances the plugging action of the talcacross or into micro fractures in sands, shale and other substances downhole.

[0035] In a further embodiment, the present invention relates to amethod of manufacturing a drilling fluid additive whereby talc andcopolymer beads are added to soybean oil and mixed or sheared until eachparticle of talc and each copolymer bead is oil wet. A first sample wasproduced by addition of 350 grams of soybean oil with 5 grams of talcand 100 grams of polymer beads to the oil, and then mixing all thecomponents for 10 minutes using a waring blender. After blending, themixture was placed in a beaker for observation. The mixture appearedhomogeneous and initially resembled buttermilk. After 5 minutes, thebeads began to settle. After one hour, all the beads settled to thebottom of the beaker and some of the oil began separating from themixture and clear oil was present at the upper portion of the beaker.After sitting overnight (10 hours later), the upper portion of thebeaker was clear oil and the bottom portion was the talc, beads and oil.Pouring the clear oil off exposed that the beads had settled and packedtightly preventing the beads from pouring out of the beaker. This samplecould not be placed in a drum or tank for shipping because the beadswould settle and plug the drum or tank.

[0036] A second sample was produced by adding talc to the oil andeliminating the beads initially. It was discovered that the oil acceptedapproximately 40% by weight of talc. After sitting overnight, there wasno separation between the talc and the oil. At that point, smalladditions of beads were added to the above mixture. The addition of 2%by weight of beads to the talc/oil mixture was encouraging. The beadssettled slightly but did not pack off. As the concentration of the beadswas increased in the mixture, it was discovered that the beads remainedsuspended in the mixture. FIG. 2 depicts graphical representations ofthe talc concentration as percent (%) by weight of oil versus thepercent (%) of beads suspended in oil. FIGS. 2 illustrates that as thetalc concentration as a percent (%) by weight of the oil increases, thesuspension qualities of the liquid oil increases. As FIG. 2 illustrates,the talc concentration of 20 percent by weight of the liquid oilsuspends 100 percent of the copolymer beads.

[0037] The second sample was then heated to 150 degrees Fahrenheit for24 hours and the copolymer beads remained suspended. The mixture wasthen cooled to 35 degrees Fahrenheit for 24 hours and the copolymerbeads remained suspended. It was also discovered that the optimumconcentration of the beads was from about 20 percent to about 30 percentby weight of the oil, and the concentration of the talc should be around20 percent by weight of oil. Although this sample appears to be thebest, the concentration may vary.

[0038] The specific examples throughout the specification will enablethe present invention to be better understood. However, they are merelygiven by way of guidance and do not imply any limitations. Example 1conducted tests on a 9.9 pounds per gallon (ppg) water-based drillingfluid and Example 2 conducted tests on a 16.9 pounds per gallon (ppg)water-based drilling fluid. Example 3 conducted tests on the reductionof capillary forces in both the 9.9 ppg drilling fluid of Example 1 andthe 16.9 ppg drilling fluid of Example 2.

EXAMPLE 1

[0039] Test 1: Rheology & HPHT Results

[0040] In Example 1, a 9.9 pound per gallon water-based drilling fluidwas tested for the (a) the compatibility of the drilling fluid-such asrheology; and the yield point and gels in particular; (b) the highpressure high temp fluid loss-HPHT; (c) the filter cake wt./gram; and(d) the filter cake thickness (in inches). Parameters were first testedon the base mud. By comparison, 2 percent (%) by volume of the oil, talcand the beads mixture was added to the base drilling fluid and mixed for5 minutes on a waring blender. In Test 1 & Table 2, the followingrheology and HPHT results were noted: TABLE 2 Rheology & HPHT ResultsBASE & 2% TALC % BASE MIXTURE REDUCTION Density 9.9 PH Meter 10.3 600rpm 19 22 300 rpm 11 13 200 rpm 8 10 100 rpm 5 6  6 rpm 2 1  3 rpm 2 1PV @ 120 F. 8 9 YP 3 4 Gels 10 sec/10 min 2/13 1/17 HPHT @ 200 Deg F./ml12.0 8.0 33% Cake Wt./g 5.9 5.4  8% Cake Thickness/inch 3/32 2/32 33%MBT/pbb 30 Solid/Oil/Water 10/00/90

[0041] The results of Example 1, Test 1 indicate the following: thetalc, bead and oil mixture was very compatible with the mud rheologywith only slight increases in yield point and gels. The HPHT fluid losswas reduced from 12.0 to 8.0; a 33% reduction, which is excellent. Thecake in weight in grams was reduced from 5.9 grams to 5.4 grams, an 8%reduction. The cake thickness in inches was reduced from 3/32 to 2/32, a33% reduction, which is also excellent.

EXAMPLE 1

[0042] Test 2: Dynamic Filtration

[0043] In Example 1, Test 2, the following dynamic filtration criteriawere tested: (a) Fluid loss versus time; (b) Filter cake wt/gram; and(c) Filter cake thickness in inches. The dynamic filtration data ofExample 1, Test 2 is set forth in Table 3 below: TABLE 3 DYNAMICFILTRATION 5 Darcy, 50 Micron Filter Media 200 Degrees F., 600 rpm @1000 PSI for 60 Minutes Fluid Loss (ml) BASE & 2% TIME (Minutes) BASETALC MIXTURE % REDUCTION Initial Spurt 1.5 trace 15 12.6 5.8 30 17.010.0 45 21.2 14.0 60 24.0 16.8 30% Cake Wt/g 10.7 5.8 46% CakeThickness/Inch 3/32 2/32 33%

[0044] The results of Example 1, Test 2 are as follows: after 60minutes, the dynamic fluid loss was reduced from 24.0 ml to 16.8 ml, a30% reduction, which is excellent. The cake weight in grams was reducedfrom 10.7 grams to 5.8 grams, a 46% reduction, which is also excellent.The cake thickness was reduced from 3/32 to 2/32, a 33% reduction, whichis excellent.

EXAMPLE 1

[0045] Test 3: Lubricity Test

[0046] Table 4 below shows the test results of the lubricity of theadditive as torque is applied. TABLE 4 LUBRICITY TEST @ 60 rpmsCo-efficient of Friction of Water (0.33-0.36) = 0.33; i.e. reading at150 inch pounds is 33 Lubricity Reading (electric current required tosustain 60 rpm at applied torque) Applied Torque/ BASE & 2% Inch PoundsBASE TALC MIXTURE % REDUCTION 100 10 11 150 16 16 200 21 21 300 31 28400 44 37 500 66 50 600 80 65 19%

[0047] The lubricity results of Example 1, Test 3 indicate animprovement in lubrication bout 19% at the 600 reading on the lubricitytester.

EXAMPLE 1

[0048] Test 4: Texture of Dynamic Filter Cake Surfaces

[0049] The texture of the filter cake surfaces and the surfaces of thebase mud were also tested. The results were as follows: the texture ofthe surface of the base mud was extremely smooth and shinny. The textureof the Dynamic Filter Cake Surface of the base mud treated with 2% byvolume of the talc, bead and oil mixture was shinny and the copolymerbeads could be seen impregnated in the cake as well as protruding on thesurface of the cake.

EXAMPLE 2

[0050] Test 1: Rheology & HPHT Results

[0051] In Example 2, a 16.9 pound per gallon water-based drilling fluidwas tested for a) the compatibility of the drilling fluid-such asrheology; and the yield point and in particular; (b) the high pressurehigh temp fluid loss-HPHT; (c) the filter cake wt./gram; and (d) thefilter cake thickness (in inches). Parameters were first tested on thebase mud. By comparison, 2 percent (%) by volume of the oil, talc andthe beads mixture was added to the base drilling fluid and mixed for 5minutes on a waring blender. In Example 2, Test 1, the followingrheology and BPHT results were noted in Table 5 below: TABLE 5 Rheology& HPHT Results BASE & 2% % BASE TALC MIXTURE REDUCTION Density 16.9 PHMeter 10.4 600 rpm 53 56 300 rpm 30 32 200 rpm 22 25 100 rpm 13 15  6rpm 2 3  3 rpm 1 2 PV @ 120 F. 23 24 YP 7 8 Gels 10 sec/10 min 4/19 5/27HPHT @ 300 Deg F./ml 15.0 13.2 12% Cake Wt./g 27.2 18.7 31% CakeThickness/inch 6/32 4/32 33%

[0052] The results of Example 2, Test 1 indicate the following: in Test2, Table 5, the talc, beads and oil mixture was very compatible with themud rheology with little change points and gel. The HPHT fluid loss wasreduced from 15.0 to 13.2, a 12% reduction, which is somewhat less thanexpected. The cake weight in grams was reduced from 27.2 grams to 18.7grams, a 31% reduction, which is a very good result. The cake thicknesswas reduced from 6/32 to 4/32, a 33% reduction.

EXAMPLE 2

[0053] Test 2: Dynamic Filtration

[0054] In Example 2, Test 2, the following dynamic filtration criteriawere tested: (a) Fluid loss versus time; (b) Filter cake wt/gram; and(c) Filter cake thickness in inches. The dynamic filtration data ofExample 2, Test 2 is set forth in Table 6 below: TABLE 6 DYNAMICFILTRATION 10 Darcy, 35 Micron Filter Media 300 Degrees F., 600 rpm @1000 PSI for 60 Minutes Fluid Loss (ml) BASE & 2% TIME (Minutes) BASETALC MIXTURE % REDUCTION Initial Spurt 1.0 0.5 15 25.2 17.6 30 38.0 25.045 46.0 31.4 60 53.2 36.0 32% Cake Wt/g 91 62 32% Cake Thickness/Inch18/32 12/32 33%

[0055] The results of Example 2, Test 2, Table 6 are as follows: after60 minutes, the dynamic fluid loss was reduced from 24.0 ml to 16.8 ml,a 32% reduction, which is an excellent result. The cake weight in gramswas reduced from 91 grams to 62 grams, a 32% reduction, which is a verygood result. The filter cake was reduced from 18/32 to 12/32, a 33%reduction, which is also an excellent result.

EXAMPLE 2

[0056] Test 3: Lubricity Test

[0057] Table 7 below shows the test results of the lubricity of theadditive as torque is applied. TABLE 7 LUBRICITY TEST @ 60 rpmsCo-efficient of Friction of Water (0.33-0.36) = 0.33; i.e. reading at150 inch pounds is 33 Lubricity Reading (electric current required tosustain 60 rpm at applied torque) Applied Torque/ BASE & 2% Inch PoundsBASE TALC MIXTURE % REDUCTION 100 14 9 150 23 12 200 30 15 300 46 20 40060 23 500 76 25 600 92 28 70%

[0058] The lubricity results of Example 2, Test 3 indicate animprovement in lubrication bout 70% at the 600 reading on the lubricitytester, which is an excellent result.

EXAMPLE 2

[0059] Test 4: Texture of Dynamic Filter Cake Surfaces

[0060] The texture of the filter cake surfaces and the surfaces of thebase mud were also tested. The results were as follows: the texture ofthe surface of the base 16.9 ppg mud was smooth and shinny. The textureof the Dynamic Filter Cake surface of the base mud treated with 2% byvolume of the talc, bead and oil mixture was shinny and the copolymerbeads could be seen impregnated in the cake as well as protruding on thesurface of the cake.

EXAMPLE 3

[0061] Reduction in Capillary Attractive Forces of Examples 1& 2

[0062] In Example 3, the (dynamic) filter cake of the base mud wasplaced on a flat surface and a piece of glass ¼ inch thick and fourinches square was placed flat on the surface of the base mud filter cakeand allowed to sit for thirty minutes. An attempt was then made to liftthe glass from the filter cake. As the glass plate was lifted, thefilter cake followed and it was as though the filter cake was glued tothe glass.

[0063] The (dynamic) filter cake of the base mud to which 2% of theadditive of the present invention was added was placed on the flatsurface and the same process discussed above was duplicated. It wasfound that the piece of glass easily separated from the filter cakesurface, which was treated with the additive of the present invention.The results show that the additive mixture of the present inventiondefinitely reduced, if not, eliminated the capillary attractive forcesof the wall cake.

[0064] Since the above tests were conducted in open air on the countertop, it was determined that the same tests should be conducted whiletotally submerged in the drilling fluid. In running the same tests withthe filter cake and the 4 inch piece of glass completely submerged inthe drilling fluid, it would be concluded that no air would be presentin the filter cake or the glass surface and such a test would resemble awellbore filled with drilling fluid. This test results were as follows:the glass plate stuck more firmly to the submerged water-based mud wallcakes than it did in open air; and the glass plate would not stick tothe wall cakes of the water-based muds, which were treated with the 2%by volume of the drilling fluid additive of the present invention.

[0065] Talc, Graphite & Carrier:

[0066] The benefits of using fine particle graphite and fine particleuintaite in drilling fluids by adding the dry products to the drillingfluids have been minimal. Over the years, graphite and uintaite(Gilsonite™) have been used to reduce fluid loss, provide lubrication,and help prevent bit and bottom hole assembly balling. Only marginalresults have been obtained by adding the dry powdered graphite anduintaite. These dry products seem to be hydrophobic by nature and do noteasily mix or disperse in the water based drilling fluids, Improving thefilter cake integrity of a drilling fluid is paramount in successfullydrilling a well. Drilling fluid specialists are constantly searching forbetter and more effective particle-plugging agents. Most frequently usedparticle plugging agents would be bentonite clay, lignite, starches,cellulose, polymers, ground mud shells, etc. In water-base drillingfluids, solids are essential to the mud system. Some of these solids arecalled commercial solids such as lignite, barite, bentonite and othersolids that are added on order to enhance the mud system. Other solidssuch as the formation being drilled or drilled solids are alsoincorporated in the drilling fluid. In water-based drilling fluids,water dilution is a necessity or the fluid becomes too thick the pump.As the solids content of the drilling fluid increases, the penetrationrate of the drill bit decreases. It is therefore desirable to achievethe maximum benefit from commercial solids which are added to thedrilling fluid by adding the smallest or least amount of commercialsolids in order to achieve sufficient particle plugging and to insuregood filter cake integrity. Dry products are added to the drilling fluidas pounds per barrel (ppb). It is an object of this invention to showthat fluid loss improvement and better filter cake integrity can beachieved with less commercial solids such as dry graphite and/oruintaite being added to the drilling fluid. This improvement can beattributed to admixing the graphite and uintaite dry powders to a liquidcarrier such as glycol and then admixing talc and 18-100 mesh copolymerbeads in order to suspend the graphite and uintaite in the liquidycarrier. The liquid graphite and uintaite suspension is more effectivewhile adding less overall solids to the drilling fluid. A graphite anduintaite suspension with carrier was formulated and the following testswere conducted:

[0067] 120 grams of glycol and 25 grams of graphite were mixed for 10minutes. To this mixture, 25 grams of uintaite was added and mixed for10 minutes. To this mixture, 10 grams of talc and 10 grams of polymerbeads was added and mixed at high speed until the mixture becameextremely hot to the touch, about 125-140 degree F. or for about 20-45minutes. The viscosity of the mite thickens initially as all of thesolids are added to the carrier but as the temperature increases to110-135 degree F. the viscosity thins down. As this point 10 grams ofwater is added and mixed for about 10 minutes. The sample is thenallowed to cool to room temperature and is now ready to be compared tothe dry products.

EXAMPLE 4

[0068] Test 1: Comparison of Dry Graphite to Liquid Graphite Mixture

[0069] The addition of 2% of the graphite dispersion is equivalent toapproximately 2 ppb of graphite as compared to 8 ppb of dry graphite.The 2 ppb of graphite in the liquid carrier clearly outperforms the 8ppb of dry graphite.

[0070] The particle sizes of the graphite and uintaite should be suchthat 100% would pass through a 200 mesh shaker screen and at least 50%would pass through a 300 mesh shaker screen The results of Example 4,Test 1 are set forth below in Table 8: TABLE 8 HPHT & Cake Wt.Comparison BASE MUD & BASE MUD & BASE 8 ppb DRY 2% GRAPHITE MUD GRAPHITEDISPERSION Density 17.3 17.3 17.3 pH Meter 11.5 11.5 11.5 600 rpm 82 11185 300 rpm 46 66 49 200 rpm 34 49 44 100 rpm 20 31 29  6 rpm 3 5 6  3rpm 2 4 5 PV @ 120 F. 36 45 36 YP 10 21 13 Gels 10 s/10 m/30 m 3/6/75/17/22 3/7/8 HPHT @ 300 Deg. F./ 8.4 7.8 5.6 ml. Cake Wt./g. 19 20 12.8Cake Thickness (Inch.) 4/32 4/32 3/32

[0071] The results of Example 4, Test 1 indicate the following: the 2%graphite dispersion showed better results than the 8 ppb dry graphite.The IHPHT fluid loss was reduced from 7.8 to 5.6; a 28% reduction, whichis excellent. The cake in weight in grams was reduced from 20 grams to12.8 grams, a 36% reduction, which is also excellent. The cake thicknessin inches was also reduced from 4/32 to 3/32.

EXAMPLE 4

[0072] Test 2: Dynamic Filtration

[0073] In Example 4, Test 2, the following dynamic filtration criteriawere tested: (a) Fluid loss versus time; (b) Filter cake wt/gram; and(c) Filter cake thickness in inches. The dynamic filtration data ofExample 4, Test 2 is set forth in Table 9 below: TABLE 9 DYNAMICFILTRATION 10 Darcy, 35 Micron Filter Media 300 Degrees F., 600 rpm @1000 PSI for 60 Minutes BASE MUD & BASE 8 ppb DRY MUD & 2% BASE GRAPHITEGRAPHITE Time/Minutes MUD Fluid Loss/ml DISPERSION Initial Spurt Trace0.0 0.0 15 7.0 3.6 1.0 30 10.8 8.8 2.8 45 13.8 11.4 4.6 60 16.0 13.6 8.2Cake Wt. (g.) 44 38 28 Cake Thickness (Inch) 8/32 7/32 5/32

[0074] The results of Example 4, Test 2, Table 9 are as follows: after60 minutes, the dynamic fluid loss was reduced from 13.6 ml to 8.2 ml, a40% reduction, which is an excellent result. The cake weight in gramswas reduced from 38 grams to 28 grams, a 26% reduction, which is a verygood result. The filter cake was reduced from 7/32 to 5/32 which is alsoa very good result.

EXAMPLE 4

[0075] Test 3: Lubricity Test

[0076] Table 10 below shows the test results of the lubricity of theadditive as torque is applied. TABLE 10 LUBRICITY TEST @ 60 rpmsCo-efficient of Friction of Water (0.33-0.36) = 0.33; i.e. reading at150 inch pounds is 33 Lubricity Meter Reading (electrical currentrequired to sustain 60 rpm at applied torque) BASE MUD & BASE MUD &Applied Torque/ BASE 8 ppb DRY 2% GRAPHITE Inch Pounds MUD GRAPHITEDISPERSION 100 11 11 8 150 17 16 12 200 23 22 21 300 34 32 28 400 44 4137 500 57 51 41 600 66 60 52

[0077] The lubricity results of Example 4, Test 3 indicate animprovement in lubrication bout 13% at the 600 reading on the lubricitytester, which is a very good result.

EXAMPLE 5

[0078] Test 1: Comparison of Dry Graphite to Liquid Graphite Mixture InA Lighter Weight Mud

[0079] The addition of 2% of the graphite dispersion is equivalent toapproximately 2 ppb of graphite as compared to 8 ppb of dry graphite ina lighter weight mud. The 2 ppb of graphite in the liquid carrierclearly outperforms the 8 ppb of dry graphite in the lighter weight mud.

[0080] The particle sizes of the graphite and uintaite should be suchthat 100% would pass through a 200 mesh shaker screen and at least 50%would pass through a 300 mesh shaker screen. The results of Example 5,Test 1 are set forth below in Table 11: TABLE 11 HPHT & Cake Wt.Comparison BASE MUD & BASE MUD & BASE 8 ppb DRY 2% GRAPHITE MUD GRAPHITEDISPERSION Density 10.7 10.7 10.7 pH Meter 10.5 10.5 10.5 600 rpm 30 3435 300 rpm 18 20 22 200 rpm 13 14 17 100 rpm 9 9 11  6 rpm 3 2 4  3 rpm2 2 3 PV @ 120 F. 12 14 13 YP 6 6 9 Gels 10 s/10 m/30 m 5/28 5/26 7/26HPHT @ 200 Deg. F./ 15.4 12.2 9.2 ml. Cake Wt. (g.) 14.0 13.0 10.5 CakeThickness (Inch) 4/32 4/32 3/32

[0081] The results of Example 5, Test 1 indicate the following: the 2%graphite dispersion showed better results than the 8 ppb dry graphite inthe lighter weight mud. The HPHT fluid loss was reduced from 12.2 to9.2; a 25% reduction, which is excellent. The cake in weight in gramswas reduced from 13 grams to 10.5 grams, a 19% reduction, which is alsoexcellent. The cake thickness in inches was also reduced from 4/32 to3/32.

EXAMPLE 5

[0082] Test 2: Dynamic Filtration

[0083] In Example 5, Test 2, the following dynamic filtration criteriawere tested: (a) Fluid loss versus time; (b) Filter cake wt/gram; and(c) Filter cake thickness in inches. The dynamic filtration data ofExample 5, Test 2 is set forth in Table 12 below: TABLE 12 DYNAMICFILTRATION 10 Darcy, 35 Micron Filter Media 300 Degrees F., 600 rpm@1000 PSI for 60 Minutes BASE MUD & 8 ppb BASE MUD & BASE DRY GRAPHITE 2%GRAPHITE TIME/Minutes MUD Fluid Loss/ml. DISPERSION Initial Spurt TraceTrace Trace 15 10.2 8.8 6.8 30 16.0 12.8 9.8 45 20.4 16.6 12.4 60 25.619.8 14.2 Cake Wt. (g.) 17.5 15.0 11.7 Cake 5/32 4/32 3/32 Thickness(Inch)

[0084] The results of Example 5, Test 2, Table 12 are as follows: after60 minutes, the dynamic fluid loss was reduced from 19.8 ml to 14.2 ml,a 28% reduction, which is an excellent result. The cake weight in gramswas reduced from 15 grams to 11.7 grams, a 22% reduction, which is avery good result. The filter cake was reduced from 4/32 to 3/32, whichis also a very good result.

EXAMPLE 5

[0085] Test 3: Lubricity Test

[0086] Table 13 below shows the test results of the lubricity of theadditive as torque is applied. TABLE 13 LUBRICITY TEST @ 60 rpmsCo-efficient of Friction of Water (0.33-0.36) = 0.33; i.e. reading at150 inch pounds is 33 Lubricity Meter Reading (electrical currentrequired to sustain 60 rpm at applied torque) BASE MUD & BASE MUD &Applied Torque/ BASE 8 ppb 2% GRAPHITE Inch Pounds MUD DRY GRAPHITEDISPERSION 100 12 11 10 150 18 17 15 200 22 20 18 300 33 30 26 400 47 4131 500 60 52 41 600 80 65 50

[0087] The lubricity results of Example 5, Test 3 indicate animprovement in lubrication was about 23% at the 600 reading on thelubricity tester, which is an excellent result.

EXAMPLE 6

[0088] Test 1: Comparison of Dry Graphite/Dry Uintaite to LiquidGraphite/Uintaite Mixture

[0089] The addition of 2% of the graphite/uintaite dispersion isequivalent to approximately 2 ppb of graphite/uintaite as compared to 4ppb of dry graphite and 4 ppb of dry uintaite. The 2% graphite/uintaitedispersion clearly outperforms the 4 ppb of dry graphite and 4 ppb ofdry uintaite.

[0090] The particle sizes of the graphite and uintaite should be suchthat 100% would pass through a 200 mesh shaker screen and at least 50%would pass through a 300 mesh shaker screen. The results of Example 5,Test 1 are set forth below in Table 14: TABLE 14 HPHT & Cake Wt.Comparison BASE MUD & BASE MUD & 4 ppb DRY 2% GRAPHITE/ GRAPHITE & 4 ppbUINTAITE BASE MUD DRY UINTAITE DISPERSION Density 16.2 16.2 16.2 pHMeter 11.5 11.5 11.5 600 rpm 91 100 102 300 rpm 54 60 58 200 rpm 40 4443 100 rpm 26 28 29  6 rpm 7 8 7  3 rpm 6 7 5 PV @ 120 F. 37 40 44 YP 1720 14 Gels 10 s/ 7/23 7/35 7/30 10 m/30 m HPHT @ 25 18.2 13.4 300 Deg.F./ ml. Cake Wt. (g.) 34 29 21 Cake 7/32 5/32 4/32 Thickness (Inch)

[0091] The results of Example 6, Test 1 indicate the following: the 2%graphite/uintaite dispersion showed better results than the 4 ppb drygraphite and 4 ppb dry uintaite. The BPHT fluid loss was reduced from18.2 to 13.4; a 26% reduction, which is excellent. The cake in weight ingrams was reduced from 29 grams to 21 grams, a 28% reduction, which isalso excellent. The cake thickness in inches was also reduced from 5/32to 4/32, a 20% reduction, which is also an excellent result.

EXAMPLE 6

[0092] Test 2: Dynamic Filtration

[0093] In Example 6, Test 2, the following dynamic filtration criteriawere tested: (a) Fluid loss versus time; (b) Filter cake wt/gram; and(c) Filter cake thickness in inches. The dynamic filtration data ofExample 6, Test 2 is set forth in Table 15 below: TABLE 15 DYNAMICFILTRATION/ 10 Darcy, 35 Micron Filter Media 300 Degrees F., 600 rpm@1000 PSI for 60 Minutes BASE MUD & 4 ppb DRY BASE MUD & GRAPHITE & 4 ppb2% GRAPHITE/ BASE DRY UINTAITE UINTAITE TIME/Minutes MUD Fluid Loss/ml.DISPERSION Initial Spurt Trace Trace Trace 15 17.4 15.2 12.0 30 27.624.0 18.2 45 35.6 30.8 23.0 60 42.4 36.4 26.2 Cake Wt./g. 69 57 41 CakeThickness/ 14/32 11/32 8/32 Inch.

[0094] The results of Example 6, Test 2, Table 15 are as follows: after60 minutes, the dynamic fluid loss was reduced from 36.4 ml to 26.2 ml,a 28% reduction, which is an excellent result. The cake weight in gramswas reduced from 57 grams to 41 grams, a 28% reduction, which is anexcellent result. The filter cake was reduced from 11/32 to 8/32, whichis also an excellent result.

EXAMPLE 6

[0095] Test 3: Lubricity Test

[0096] Table 16 below shows the test results of the lubricity of theadditive as torque is applied. TABLE 16 LUBRICITY TEST @ 60 rpms/Co-efficient of Friction of Water (0.33-0.36) = 0.33; i.e. reading at150 inch pounds is 33 Lubricity Meter Reading (electrical currentrequired to sustain 60 rpm at applied torque) BASE MUD & BASE MUD & 4ppb DRY 2% GRAPHITE/ Applied Torque/ BASE GRAPHITE & UINTAITE InchPounds MUD 4 ppb DRY UINTAITE DISPERSION 100 8 7 6 150 12 10 9 200 17 1413 300 28 24 21 400 36 32 25 500 44 38 30 600 64 49 37

[0097] The lubricity results of Example 6, Test 3 indicate animprovement in lubrication was about 25% at the 600 reading on thelubricity tester, which is an excellent result.

[0098] Numerous modifications and variations of the present inventionare possible in light of the above teachings. It is therefore to beunderstood that within the scope of the attendant claims attachedhereto, this invention may be practiced otherwise than as specicallydisclosed herein.

What is claimed is:
 1. A drilling fluid additive comprising: talc,graphite and at least one carrier.
 2. The drilling fluid additive ofclaim 1 further comprising uintaite.
 3. The drilling fluid additive ofclaim 1 wherein said carrier comprises polypropylene glycol.
 4. Thedrilling fluid additive of claim 1 wherein said carrier is selected froma group consisting of oils, esters, glycols, cellulose, olefins andmixtures thereof.
 5. The drilling fluid additive of claim 2 wherein saidtalc comprises from about 1% to about 20% of said additive, saidgraphite comprises from about 1% to about 30% of said additive, saidcarrier comprises from about 50% to about 90% of said additive and saiduintaite comprises from about 1% to about 40% of said additive.
 6. Thedrilling fluid additive of claim 1 wherein said carrier is selected froma group consisting of polypropylene glycol, polyethoxylated glycol,polybutylene glycol, polyethylene glycol, propylene glycol, polyesterpolyol-poly(oxyethylene-oxy) propylene glycol, polyoxyalkylene glycolethers and mixtures thereof.
 7. The drilling fluid additive of claim 1wherein said uintiate is treated with a second carrier.
 8. The drillingfluid additive of claim 7 wherein said second carrier is selected from agroup consisting of oils, esters, glycols, cellulose, olefins and mixesthereof.
 9. The drilling fluid additive of claim 1 wherein said secondcarrier comprises an ethoxylated glycol.
 10. A drilling fluid additivemanufactured by a method comprising: admixing talc, graphite and atleast one carrier.
 11. The drilling fluid additive of claim 10 whereinsaid carrier is first admixed with said talc and then the graphite isadmixed.
 12. The drilling fluid additive of claim 10 further comprisingadmixing an uintaite with said carrier, talc and graphite mixture. 13.The drilling fluid additive of claim 10 wherein said carrier is selectedfrom a group consisting of oils, esters, glycols, cellulose, olefins andmixtures thereof.
 14. The drilling fluid additive of claim 12 whereinsaid uintaite is pre-treated with a second carrier prior to beingadmixed to said carrier, talc and graphite mixture.
 15. The drillingfluid additive of claim 12 wherein said talc comprises from about 1% toabout 20% of said additive, said graphite comprises from about 1% toabout 30% of said additive, said carrier comprises from about 50% toabout 90% of said additive and said uitaite comprises from about 1% toabout 40% of said additive.
 16. The drilling fluid additive of claim 10wherein said second carrier is selected from a group consisting of oils,esters, glycols, cellulose, olefins and mixtures thereof.
 17. A methodof manufacturing a drilling fluid additive, said method comprising:admixing talc with at least one carrier; and admixing graphite to saidtalc and carrier mixture.
 18. The method of claim 17 further comprisingadmixing an uintaite with said talc, carrier and graphite mixture. 19.The method of claim 18 wherein said uintaite is pretreated with a secondcarrier prior to admixing said uintaite to said talc, carrier andgraphite mixture.
 20. The method of claim 19 wherein said first andsecond carriers are selected from a group consisting of oils, esters,glycols, cellulose, olefins and mixtures thereof.